1. Field of the Invention:
This invention relates to bending glass plates and optionally also their tempering, and it relates more particularly to an installation for bending and optionally tempering in which said glass plates are bent by being transported on a conveyor whose elements of support of the glass plates are placed along a curved path.
This bending technique, optionally including heat tempering, is more particularly described in French Pat. document No. 2 422 219, U.S. Pat. No. 4 540 426 and European Pat. document No. 263 030. In these documents, conveyors with rectilinear rollers are described whose axes form a curved path, descending or preferably rising. These conveyors are able to give glass plates brought to their bending temperature, and therefore deformable under the effect of gravity, a simple bend, i.e. in a single direction, or a cylindrical bend, when they pass on these conveyors. Conveyors with curved rollers or rods are also described whose axes form, as before, a curved path, thus constituting for the glass plates thereon heated to bending temperature, a double bend shaping bed to produce both a bend in the direction of travel of the glass plates by the arrangement of the rollers or rods in the curved path, and a crosswise bend in the direction perpendicular to the direction of travel, by the curved shape of the rollers or rods.
U.S. Pat. No. 4,540,426, already cited, also proposes a recovery of the glass plates at the upper end of the bending and tempering device with a curved profile in the direction of advance of the glass plates. This recovery is performed by a swinging device in which each glass plate engages at the end of the bending and tempering operation. The device swings under the projection effect created by the weight of the glass plate and deposits the plate on a conveyor which does not have a greatly tilted inclined orientation of the end of the bending and tempering device, but has a different orientation such as approximately horizontal. After having swung each glass plate onto the evacuation conveyor, the swinging device freed from the projection created by the glass plate returns by swinging in the opposite direction to its initial position, waiting for the next glass plate.
This swinging device is generally satisfactory, but the swinging time in the opposite direction to return to receiving position for a new glass plate is essentially troublesome because it limits the rate of this bending-tempering technique. Actually, according to this technique, the glass plates could follow one another at a higher rate, practically without intervals between them, if there were no need to await the return of the swinging device to its receiving position.